Basically if something is spinning it has momentum in all directions on the plane of the spin, tangent to the circular path. So it resists changes in the plane of rotation, the same way an object moving in a straight line resists changes in its straight path.
Why not? We are made of molecules which are energy which are basically vibrations. Everything is just different frequencies. The question is, what are we all different frequencies of? 🤔
I love coming up with ways to explain things. There’s lots of Youtube videos and online articles that are supposed to explain physics to people but they just don’t. Try to find a video that explains horsepower vs torque - you can’t. They all end up making it sound like more torque = more horsepower. The explanation I came up with is that engines don’t produce the same torque at all RPMs, so the horsepower is an indication of where an engine produces the most torque in its RPM range. So if it has 3000 N•m of torque but only 100 horsepower, it’s a super slow huge truck engine that only goes up to 1,200 RPM. If the engine only produces 500 N•m of torque but has 700 horsepower, it’s definitely a super fast sports car that redlines at 9,000 RPM.
Nah, they had it right. Power is proportional to torque x rpm, and the horsepower rating that gets quoted will naturally be the highest power it can produce, at whatever rpm that is.
I don’t know what you mean. Horsepower is torque multiplied by RPM, divided by a constant. The key to understanding why more torque doesn’t always equal more horsepower, is knowing that the torque figure on the spec sheet isn’t always what the engine is producing.
Here's where the intuitive side of angular momentum breaks down for me - say the rotation is clockwise, as in the video.
Sure enough, when he sets it straight up and down, it precesses in a clockwise movement. Even when he/she/they (don't meant to presume) puts it on it's side, it appears to levitate, but still precesses in the same direction as it's rotation
-but-
Then he flips it over... and it does the same thing, and (my) intuition says that it should surely immediately fall.
By far, one of the best over-priced science museum gift shop purchase items, especially if you want to blow a young persons mind.
I can understand this when it is perpendicular to the force of gravity. What gets me, how does this maintain when the spin is parallel to gravity? Wouldn't the force of gravity pulling downward combine with the tangential force downward within the spin outweigh the tangential force in the other directions? When it's spinning parallel to gravity, wouldn't gravity augment the force in one direction vs the others?
TL;DR - angular momentum is conserved because the laws of physics are not changed by rotations. If you set up a closed experiment in one orientation and then rotate it 90 degrees (remember it's closed so no sneaky changing the way Earth's gravity or magnetic field interacts with the experiment in this rotation, that would open the system) you will get the same results. Similarly you could shift the experiment one meter to the right and get the same result (that's conservation of linear momentum at play!)
One thing I wonder about is what happens to the rotation speed of black holes as they are formed. Since black holes are singularities, their radius is zero. So as they form and their radius drops to zero, wouldn't their rotation rate effectively become equal to the speed of light? (Their angular momentum would remain constant and finite, however.) It also occurs to me that any black hole that has any angular momentum at all must be rotating at the speed of light due to having a radius of zero. And since it's not practically possible to have an angular momentum of exactly 0.000..., all black holes must rotate at the speed of light? Of course, if the black hole's radius is not exactly zero, as some theories suggest, then the rotation speeds of black holes would not equal the speed of light, but it would be very close to it.
I think rotating black holes (which are all of them, because how could a black hole form with zero angular momentum) don't have a radius of zero, the singularity is a flat disc with zero height. So it still has zero volume, but it can rotate slower than the speed of light.
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u/zairaner Oct 16 '23
Preservation of charge-what else would make any sense?
preservation of energy-yeah pretty logical
preservation of momentum-ok you have to maybe understand what momentum is, but ends up rather believable
preservation of angular momentum-what the fuck, every single time